NNPA and Tynedale District Joint Strategic Flood Risk Assessment
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Tynedale District Council & Northumberland National Park Authority Level 1 Strategic Flood Risk Assessment April 2009 FINAL REPORT JBA Consulting Contracting Authority: The Brew House Wilderspool Park Tynedale District Council Greenhall's Avenue Old Grammar School, Hallgate, WARRINGTON HEXHAM, Northumberland WA4 6HL UK Northumberland National Park t: +44 (0)1925 437 020 Authority f: +44 (0)1925 437 029 Eastburn, South Park, HEXHAM, [email protected] Northumberland Tynedale District Council & Northumberland National Park Tynedale Strategic Flood Risk Assessment 2007s2721 REVISION HISTORY Revision Ref./ Amendments Issued to Date Issued Draft Submission Rob Naples, Tynedale District 05 June 2008 Council (Digital Copy) David Coverdale, Northumberland National Park (Digital Copy) Draft Submission Cameron Sked, Environment 15 July 2008 Agency (Digital Copy) Final Draft Submission Comments included from: Rob Naples, Tynedale District 20 January 2009 NNPA, Tynedale District Council Council (Digital Copy) and Environment Agency David Coverdale, 05/08/08 Northumberland National Park (Digital Copy) Cameron Sked, Environment Agency (Digital Copy) CONTRACT This draft report describes work commissioned by Tynedale District Council and Northumberland National Park. The client‟s representatives for the contract were Rob Naples and David Coverdale. Jonathan Cooper, Ann-Marie Gray, James Cheetham of JBA Consulting carried out the work. Prepared by: Ann-Marie Gray, BSc MSc Assistant Analyst James Cheetham, BSc MSc PhD Analyst Reviewed by: George Heritage BSc PhD Technical Director Approved by: Jonathan Cooper, BEng MSc CEng MICE MCIWEM MiOD Divisional Manager PURPOSE This document has been prepared solely as a report for Tynedale District Council and Northumberland National Park. JBA Consulting accepts no responsibility or liability for any use that is made of this document other than by the Client for the purposes for which it was originally commissioned and prepared. JBA Consulting www.jbaconsulting.co.uk N:\2007\Projects\2007s2721 - Tynedale Council - Tyndale Council SFRA\Graphical Data\Deliverables\Report\Word\2007s2721 Tynedale FINAL_090416.doc: 22/04/2009 i Tynedale District Council & Northumberland National Park Tynedale Strategic Flood Risk Assessment 2007s2721 CONTENTS Page REVISION HISTORY i CONTRACT i PURPOSE i CONTENTS ii LIST OF FIGURES iv LIST OF TABLES iv LIST OF MAPS iv ABBREVIATIONS vii GLOSSARY viii 1 INTRODUCTION ----------------------------------------------------------------------------------------------------- 1 1.1 Overview ........................................................................................................................................ 1 1.2 Study Area ..................................................................................................................................... 1 1.3 Study Objectives ............................................................................................................................ 2 1.4 Format of the SFRA and Key Outputs ........................................................................................... 3 2 INTEGRATED FLOOD RISK MANAGEMENT WITHIN LOCAL AUTHORITY PLANNING ------ 4 2.1 Introduction – Flood Risk Management Policy Drivers.................................................................. 4 2.2 National Planning Policy ................................................................................................................ 4 2.3 Regional Planning Policy ............................................................................................................. 10 2.4 Local Plans Context ..................................................................................................................... 14 2.5 Balanced Sustainable Approach ................................................................................................. 21 3 RISK BASED APPROACH TO STRATEGIC ASSESSMENT OF FLOOD RISK ----------------- 22 3.1 Introduction .................................................................................................................................. 22 3.2 Background to Strategic Flood Risk Management Objectives .................................................... 23 3.3 The Risk Assessment Process .................................................................................................... 23 3.4 The Risk Based Sequential Approach: Overview ........................................................................ 24 3.5 Delineation of the Flood Risk Zones............................................................................................ 27 3.6 The Sequential Test – a sieving process .................................................................................... 30 3.7 Stepwise sequentially applied search ......................................................................................... 32 3.8 The Exception Test ...................................................................................................................... 39 4 SFRA FLOOD RISK MAPS ------------------------------------------------------------------------------------- 42 4.1 Introduction .................................................................................................................................. 42 4.2 Maps Overview ............................................................................................................................ 42 4.3 SFRA Risk Maps: Interpretation and use .................................................................................... 43 4.4 General Map ................................................................................................................................ 43 4.5 Fluvial Flood Extent ..................................................................................................................... 44 4.6 Functional Floodplain and Climate Change Risk Map ................................................................ 44 4.7 Surface Water Flooding Maps ..................................................................................................... 44 4.8 Conclusion and Further use of SFRA Flood Risk Maps .............................................................. 45 5 APPLICATION OF SEQUENTIAL AND EXCEPTIONS TESTS AT SUGGESTED OPTIONS FOR CONSIDERATION AS LDF SITE ALLOCATIONS ------------------------------------------------ 47 5.1 Introduction .................................................................................................................................. 47 5.2 Tynedale District Council & Northumberland National Park Area ............................................... 47 5.3 Flooding from other sources ........................................................................................................ 48 6 GUIDANCE FOR DETAILED FLOOD RISK ASSESSMENTS ----------------------------------------- 50 6.1 Introduction .................................................................................................................................. 50 6.2 General Principles ....................................................................................................................... 51 6.3 Assessment and Mitigation of Fluvial Risk .................................................................................. 52 JBA Consulting www.jbaconsulting.co.uk N:\2007\Projects\2007s2721 - Tynedale Council - Tyndale Council SFRA\Graphical Data\Deliverables\Report\Word\2007s2721 Tynedale FINAL_090416.doc: 22/04/2009 ii Tynedale District Council & Northumberland National Park Tynedale Strategic Flood Risk Assessment 2007s2721 CONTENTS Page 6.4 Assessment of Surface Water Drainage Issues .......................................................................... 52 6.5 Sustainable Urban Drainage systems (SUDS) ............................................................................ 53 6.6 Flood Zone 3b – The Functional Floodplain ................................................................................ 55 6.7 Flood Zone 3a – High Probability ................................................................................................ 55 6.8 Other Known Flood Risk Areas ................................................................................................... 62 7 CONCLUSION ------------------------------------------------------------------------------------------------------ 63 7.1 Introduction .................................................................................................................................. 63 7.2 Level 2 SFRA ............................................................................................................................... 63 7.3 Surface Water Management Plans.............................................................................................. 63 7.4 Water Cycle Studies .................................................................................................................... 64 APPENDIX A: - TYNEDALE DISTRICT COUNCIL & NORTHUMBERLAND NATIONAL PARK: SEQUENTIAL AND EXCEPTION TESTS ------------------------------------------------------------------- 67 A.1 TYNEDALE DISTRICT COUNCIL & NORTHUMBERLAND NATIONAL PARK AREA --------- 68 A.1.1 Allendale ...................................................................................................................................... 68 A.1.2 Bellingham ..................................................................................................................................